PART SIX
The Conquest of Northern Luzon

Chapter XXIVNorthern Luzon:
The Situation and the Plans

Almost from the hour of the assault
at Lingayen Gulf, Sixth Army's task on
Luzon was complicated by the fact that
the army was compelled to fight many
battles simultaneously on widely separated
fronts. In late February General
Krueger's Forces were in action at Manila,
on Bataan and Corregidor, against
the Kembu Group west of Clark Field,
and against the Shimbu Group in the
mountains east of Manila. Krueger had
already ordered XIV Corps to project
some of its strength into southern Luzon.
I Corps, having captured San Jose and
seized control over the junction of
Routes 3 and 11 near Rosario, had but
recently completed operations to secure
the Sixth Army's base area and flanks
and to provide protection to XIV Corps'
rear. Now General Krueger was preparing
to launch still another offensive, and
had alerted I Corps to make ready to
strike into northern Luzon against the
Shobu Group.

The Terrain and the Defenses
in Northern Luzon

The General Situation

By the beginning of February I Corps
had attained excellent positions from
which to strike north against the Shobu
Group, the strongest concentration of
Japanese strength on Luzon, but General
Krueger had had to postpone a
concerted offensive in northern Luzon.
General MacArthur's redeployment and
operational directives of early February
had restricted the Sixth Army's freedom
of maneuver, concomitantly reducing
its strength. General Krueger had therefore found it impossible to concentrate
adequate forces for an immediate, major
thrust against the Shobu Group. At
least until XI and XIV Corps could
assure the successful outcome of operations
to secure the Manila Bay area,
Krueger decided, he could not start I
Corps northward in a determined drive
against the Shobu Group. The strength
left to the corps--three divisions instead
of the five or more Krueger had expected
to be able to employ in northern Luzon--was not enough.1

Krueger realized only too well that
any delay in starting an attack north
against the Shobu Group would inevitably
redound to the advantage of the Japanese.
By mid-February, at least, the
Sixth Army commander had sufficient
information at his disposal to conclude
that the Shobu Group was beginning to
realign its forces for a protracted stand

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in the mountains of north Luzon, and
he hoped the Japanese would not have
too much time to dig in. What Krueger
did not know was that General Yamashita
had long had plans to move the
Shobu Group into the triangular redoubt
in northern Luzon, that Yamashita's
troops had been readying defenses
in the mountains since late December,
and that Yamashita had initiated a general
withdrawal into the mountains
before the end of January.2

Among Yamashita's major concerns
through February were the reorganization
and rehabilitation of units Sixth
Army had battered during January, and
the problem of deploying these units,
as well as others not yet committed, in
the most effective positions for the defense
of the triangular redoubt. The
Shobu Group also had to move to centrally
located depots the supplies shipped
north from Manila and Central Plains
dumps during December and January.
The Japanese would likewise have to
gather food from the rich Cagayan
Valley and distribute it to troops
throughout northern Luzon's mountains.
Time was of the essence in all
the Shobu Group preparations. No relationship
of time to defensive plans
was more important than that involved
in retaining control over the resources
of the Cagayan Valley, for the group
had been cut off from all outside sources
of supply.

Heartland and rice bowl of northern
Luzon, the Cagayan Valley averages 40
miles in width and extends from Aparri
on Luzon's northern coast south nearly
200 miles to Bambang on the Magat
River.3
On the east the rugged and
partially unexplored northern portion
of the Sierra Madre, a 35-mile-wide barrier,
separates the Cagayan Valley from
the Pacific Ocean. West of the valley
lies the equally rough Cordillera Central,
which with the coastal Ilocos Mountains--also known as the Malaya Range--forms a 70-mile-wide barrier between
the Cagayan Valley and the South China
Sea. The complex Caraballo Mountains,
forming a link between the southern
reaches of the Cordillera Central
and the Sierra Madre, block access to
the Cagayan Valley from the Central
Plains. (Map 19)

Except across the Aparri beaches, the
entrances to the Cagayan Valley follow
winding, ill-paved roads and trails
through tortuous mountain passes. Coming
north from San Jose, gravel-paved
Route 5, scarcely two lanes wide, twists
over the Caraballo Mountains into the
Magat Valley via Balete Pass. Route 11,
the other main road from the south,
leads northeast from Baguio fifty miles
to Bontoc, the northern apex of the
Shobu Group's defensive triangle. Traversing
spectacularly beautiful but rough
mountain country, Route 11 in 1945
was gravel and rock paved and varied
between one and two lanes in width.
From Bontoc Route 11, hardly more
than a horse trail, follows the rugged,
deep gorge of the Chico River northeast
to the northern section of the Cagayan
Valley.

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Map 19
Troop Dispositions
Northern Luzon
21 February 1945

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BONTOC, The Northern Apex

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Baguio is reached by coming up the
Bued River gorge from the Routes 3-11
junction near Rosario, following an
asphalt-paved, two-lane section of Route
11. Route 9, another paved road, leads
to Baguio from the South China Sea
coast at Bauang, 20-odd miles north of
Damortis. From Libtong, 55 miles north
of Damortis, narrow, gravel-paved
Route 4 leads through unbelievably
precipitous terrain to a junction with
Route 11 at Sabangan, a few miles
southwest of Bontoc. Joining Route 11
as far as Bontoc, Route 4 then turns
southeast to the Magat River and a
junction with Route 5 at Bagabag, 30
miles northeast of Bambang.

The easiest entrance to the Cagayan
Valley is at Aparri. The next best,
since it provides direct access to the
southern portion of the Cagayan Valley,
is Route 5 via Balete Pass. Route 11
northeast from Baguio is a poor third
choice, and, like all other entrances except
Route 5 and Aparri, is so tortuous
as to preclude its employment for major
military operations.

Japanese Defense Plans

The military problems presented by
the topography of northern Luzon impose
upon attacker and defender alike
a peculiar combination of concentration
and dispersion of forces.4
Yamashita's
problem was further complicated by his
plan to establish a triangular redoubt
and simultaneously retain control of the
Cagayan Valley for as long as possible.
He would have to concentrate strength
at the three apexes (Baguio, Bontoc, and
Bambang) of his defensive triangle, but
he would also have to deploy forces to
defend all possible approaches to the
Cagayan Valley.

Yamashita based his defensive deployment
upon the assumption that Sixth
Army would make its main efforts on
the Baguio and Bambang fronts. He
did not, however, ignore the other approaches
to his triangular redoubt and
the Cagayan Valley, and he took into
consideration the possibility that Sixth
Army might stage an airborne assault
into the valley. He held at Aparri about
two regiments of infantry and two battalions
of artillery, all under the control
of Headquarters, 103d Division. On
Luzon's northwest coast--in the Vigan-Laoag area--he stationed the Araki
Force, the equivalent of a regimental
combat team and formed from various
103d Division and provisional units.
Initially, an understrength independent
infantry battalion of the 103d Division
held Route 4 inland from Libtong.

The 19th Division was originally responsible
for holding the coast south
from Libtong and for blocking Route 9
from Bauang to Baguio. During January
Filipino guerrillas became so active
along Route 4 and on Route 11 between
Bontoc and Baguio that Yamashita began
to fear an amphibious assault in
the vicinity of Libtong and a subsequent
American drive inland to Bontoc. Accordingly,
he decided to move the bulk
of the 19th Division north to hold Bontoc,
clear Route 4 west to Libtong, and

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drive the guerrillas off the Baguio-Bontoc
section of Route 11. The movement
started late in February.

The transfer of the 19th Division
necessitated realignment of forces on the
Baguio front, and Yamashita had begun
reshuffling troops there before the end
of February. The 58th IMB started
pulling north to defend Route 9 and to
block some mountain trails leading toward
Baguio between Route 9 and the
section of Route 11 south of Baguio.
The Hayashi Detachment, a regiment-sized
provisional unit that held the region
from Bauang to San Fernando,
passed to the control of the 58th IMB.
Simultaneously, the 23d Division began
establishing a new main line of resistance
across Route 11 at Camp 3, between Rosario
and Baguio. The division's right was
to extend northwest to connect with the
58th IMB left; the division's left would
stretch southeast almost fifteen miles
across the Arodogat River valley to the
upper reaches of the Agno River. The
Arodogat provided an axis along which
American troops might outflank Route
11 defenses on the east, while the gorge
of the upper Agno led to roads running
into Baguio from the southeast. The
Agno's canyon also provided a route to
the Baguio-Aritao supply road that Yamashita
was constructing as a link between
his Baguio and Bambang apexes.

The net effect of these realignments
on the west was to strengthen the defenses
in front of Baguio. The Japanese
forces regrouped along a narrower front,
permitting them to employ their dwindling
strength to the best advantage;
they provided for protection along all
flanking routes; and they moved into
terrain even more favorable for defense
than that the 23d Division and 58th
IMB had held during the fight for the
Routes 3-11 junction.

To guard the northern Cagayan Valley
against airborne assault, the 103d Division
stationed a reinforced infantry battalion
at Tuguegarao. Here, 50 miles
south of Aparri, were located airfields
that the Japanese Naval Air Service had
employed since the early months of the
war in the Pacific. For the same purpose
the Takachiho Unit, a provisional infantry
regiment formed from 4th Air
Army ground troops, some antiaircraft
units, and a few paratroopers, held various
4th Air Army fields at Echague, 65
miles south of Tuguegarao and 30 miles
northeast of Bagabag.

As of early February 5,000 to 7,000
men of the 105th Division--the rest of
the division was with the Shimbu Group
east of Manila--held Bagabag and Bambang.
This force included a regiment,
less one battalion, of the 10th Division.
Initially stationed in the Bambang area
to stamp out guerrilla activity, the 10th
Division regiment redeployed southward
late in the month.

The defense of the approaches to
Bambang from San Jose was anchored
on an MLR crossing the Caraballo
Mountains and Route 5 about midway
between the two towns.5
The key area
along the San Jose-Bambang stretch of
Route 5 was the Balete Pass-Sante Fe
region, nearly twenty-five miles into the

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BAGUIO

Caraballo Mountains from San Jose.
Lying three miles north of the pass,
Santa Fe is the terminus of the Villa
Verde Trail, which winds northeast from
the Central Plains over a spur of the
Caraballo range west of Route 5. Balete
Pass is located at the northern exits of
the most tortuous terrain Route 5
traverses on its way north.

Responsibility for the defense of the
Route 5 approach to Bambang was
vested in the 10th Division. Although
the Japanese estimated that the main
effort of any Sixth Army attack toward
Bambang would come up Route 5, the
10th Division was instructed to guard
all flanking approaches carefully. The
Villa Verde Trail provided a route for
outflanking the Route 5 defenses at
least as far north as Santa Fe, and near
its eastern end provided access to the
river valleys by means of which a flanking
force could move north, west of
Route 5, almost to Bambang, cutting
the supply road to Baguio on the way.
East of Route 5 lay Route 100, a third-class
road that, beginning in the foothills
ten miles southeast of San Jose,
swung to the northwest through Carranglan
and came into Route 5 at
Digdig, midway between San Jose and
Balete Pass. From Carranglan a rough
trace known as the Old Spanish Trail--of which there were dozens in the Philippines--ran north through the Sierra
Madre to Route 5 at Aritao, eastern
terminus of the new supply road to
Baguio and over halfway from Balete
Pass to Bambang. Finally, lying between
the Villa Verde Trail and the Agno
Valley is the valley of the Ambayabang
River. By trail connection to the Agno,

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the Ambayabang Valley offered a possible
route of access to Baguio from the
southeast and along its own length, as
well as by the Agno connection, provided
other routes by which Sixth Army
troops might push north to cut the
Baguio-Aritao supply road. The front
assigned to the 10th Division stretched
from the upper Ambayabang southeast
over twenty-five miles to Carranglan.
It is presumed that some tie-in with the
23d Division on the Baguio front was
to be made along either the Agno or
the Ambayabang Rivers.

In providing for defense of the various
flanking routes, the Japanese expected
that the Old Spanish Trail-Route 100
approach might well be the location of
a secondary attack. The Japanese considered
the terrain on that approach less
formidable than that along the Villa
Verde Trail, which, the Japanese
thought, Sixth Army might use only for
a very minor diversionary attack. Thus,
of the three understrength RCT's or
equivalent available to the 10th Division
as of early February--troops that
included organic units, attached regularly
organized regiments and battalions,
and provisional units of all sorts--one
RCT was posted to hold the Route 100-Old Spanish Trail junction at Carranglan
and that section of Route 100 lying
between Carranglan and Route 5. A
force roughly equivalent to an infantry
battalion held the southwestern section
of the Villa Verde Trail and another
battalion, plus a battery of artillery, was
stationed on the central section of the
trail. One provisional infantry battalion
was scheduled to move into the
Ambayabang Valley.

Originally, the rest of the 10th Division
was to hold an MLR across Route 5
near barrio Minuli, roughly five miles
south of Balete Pass. However, by early
February, when the fall of San Jose to
the U.S. I Corps presaged an immediate
attack north along Route 5, defenses in
the Minuli area were by no means in
shape to withstand a sudden onslaught.
Therefore, seeking to gain time for defense
construction along the MLR, the
10th Division deployed an RCT-sized
delaying force across Route 5 at Puncan,
a barrio lying about ten miles north of
San Jose and the same distance south of
Minuli. The remainder of the division
worked feverishly on the defenses of the
MLR.

One other unit was available on the
Bambang front--the shattered 2d Tank
Division, which had been destroyed as
an armored force in the defense of the
approaches to San Jose during January.
Less a 250-man group operating on the
Villa Verde Trail and in the Ambayabang
River valley, the 2d Tank Division
reassembled at Dupax, just off Route 5
near Aritao. There, early in February,
the division started reorganizing, re-equipping,
and retraining as an understrength
infantry division, weaving into
its depleted ranks casuals, replacements,
and provisional units of all sorts.

A description of Yamashita's special
command arrangements completes the
outline of Japanese defensive preparations
in northern Luzon. As held true
throughout the course of the Luzon
Campaign, Yamashita was plagued by
inadequate communications in northern
Luzon, posing for him major problems
of command and control. For the Bambang
area he therefore set up what
amounted to a corps headquarters under
Maj. Gen. Haruo Konuma, a vice chief
of staff of the 14th Area Army. As commander

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of the Bambang Branch, 14th
Area Army, General Konuma was to
control the operations of the 10th and
105th Divisions and the 2d Tank Division,
as well as independent units in the
area, within the framework of broad
directives issued by Yamashita. Yamashita
himself kept his headquarters at
Baguio, retaining direct control over
operations on the Baguio and Bontoc
fronts.

The Sixth Army's Plan

Sixth Army's plans for operations
against the Shobu Group did not spring
full grown into being with I Corps'
arrival on the Damortis-San Jose-Baler
Bay line.6
Indeed such plans as existed
at the beginning of February had to be
discarded for the most part as the original
allocations of divisions to Sixth Army
were cut back and more information
was accumulated concerning Japanese
strength, dispositions, and intentions in
northern Luzon. There was no "set
piece" plan of operations such as that of
the Shobu Group. Instead, Sixth Army's
plan was evolutionary in character.

Early Plans

It was General Krueger's first intention
to concentrate his forces first on the
Baguio front and Luzon's west coast
from Damortis north to San Fernando.
The early capture of Baguio would produce
certain obvious tactical advantages
and would also have propaganda value
since the city was the site of Yamashita's
combined 14th Area Army-Shobu
Group headquarters. The development
of the port at San Fernando would ease
the burden upon overtaxed Lingayen
Gulf facilities and would provide an
additional base area from which operations
in northern Luzon could be
supported.7

Krueger originally planned to use two
divisions in the Baguio-San Fernando
area--the 43d, already on the ground,
and the 33d, which reached Luzon on
10 February. While these two were
making the main effort, the 25th and
32d Divisions would operate on the
Bambang front in what at first was expected
to be a holding attack.8
Lack of
resources made it impossible for Sixth
Army to plan an airborne invasion of
the Cagayan Valley, but General
Krueger, through February and March,
did hope to mount attacks in northern
Luzon in addition to those contemplated
for the Baguio and Bambang fronts. He
planned that one division (the 37th)
would undertake a series of shore-to-shore
operations along the west coast
north from Damortis, presumably as far

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as Libtong and Vigan, the operations
to begin in late March or early April.
Krueger also considered the possibility
of mounting an amphibious operation
against Aparri by late May.9

Thus, Krueger's early plans for operations
in northern Luzon called for the
employment of four divisions on the
Baguio and Bambang fronts in simultaneous
attacks that would start after
mid-February. He would commit a fifth
division along the west coast by April
and would possibly employ a sixth at
Aparri during May. The plans never
came to fruition.

Factors Affecting the Plan

General MacArthur's redeployment
and operational directives of early February
not only made it impossible for
Krueger to concentrate forces for a major
offensive against the Shobu Group
but also forced Krueger to make sweeping
changes in all existing or tentative
plans for operations in northern Luzon.
The most immediate effect of MacArthur's directives was the relief of the
43d Division and the 158th RCT in
the Damortis-Rosario area and the replacement
of those units with the 33d
Division. The next move was the redeployment
of the 6th Division south to
Bataan and the Shimbu front. In a
week, I Corps lost one and one-third
divisions.

Even though the redeployment of the
43d Division and the 158th RCT left
only one division available for the
Baguio front, Krueger still wanted to
make his main effort on that front. The
32d Division, which had moved into a
sector between the 25th and 43d Divisions
in late January, could be made to
substitute for the 43d Division. The 32d
could swing northwest up the Ambayabang,
Agno, and Arodogat River valleys
from the south and southeast, while the
33d Division could drive north toward
Baguio via Route 11.10
Under this concept,
any effort by the 25th Division, left
alone on the Bambang front by the redeployment
of the 6th Division, would
certainly be relegated to the status of a
holding attack.

Before Sixth Army could work out
the details of such a plan, the results
of I Corps operations during February
prompted new changes. The corps' primary
missions after the advance to San
Jose were to protect Sixth Army's left
rear and block any attempts by the Japanese
to move south out of the mountains.
Krueger also directed the corps to reconnoiter
northward and gave it permission
to stage local attacks to improve
positions and feel out Japanese strength
in anticipation of a later all-out offensive
on either the Baguio or the Bambang
front.11

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In accordance with these concepts, I
Corps ordered the 43d Division--which
was not relieved until 15 February--to
secure the terrain gained by the end of
January, locate and develop Japanese
positions north of the Damortis-Rosario
section of Route 3, and maintain pressure
against Japanese units holding out
along the Hill 600-Hill 1500 ridge line
east of the Rosario-Pozorrubio section
of Route 3. The division, to which the
158th RCT remained attached, was also
instructed to avoid involvement in a
battle of such proportions that it might
have to commit the bulk of its strength.

Following these instructions, the 158th
RCT found unmistakable signs of a general
Japanese withdrawal in the area
north of the Damortis-Rosario road and
discovered that the coast line was clear
of Japanese for at least fifteen miles
north of Damortis.12
The 43d Division,
on the other hand, found the Japanese
determined to hold Route 11 northeast
from Rosario, and every attempt to
penetrate Japanese defenses along the
Hills 600-1500 ridge line brought about
an immediate Japanese counterattack.
Moreover, 43d Division patrols, including
many the attached guerrillas conducted,
were unable to move up the
Arodogat River valley in the face of a
strong Japanese counterreconnaissance
screen.

When the 33d Division took over
from the 43d Division and the 158th
RCT on 15 February, the 33d had
orders to concentrate for a drive up the
coast to San Fernando--Sixth Army was
still contemplating the idea of swinging
the 32d Division back northwest toward
Baguio. Accordingly, I Corps directed
the 33d Division to clear the Hills 600--1500 ridge line in order to secure the
division's right (east) flank before moving
to the coast. The division would
also continue reconnaissance northward
to develop Japanese positions and seek
avenues of approach toward Baguio
other than Route 11.13

The 33d Division's left (west) flank
units, probing north after 15 February,
learned that the 58th IMB withdrawal
was well under way.14
In the center,
division units patrolling northward
along both sides of Route 11 found, as
had the 43d Division, that Japanese delaying
positions and counterreconnaissance
operations blocked the road.
Finally, I Corps' instructions to clear the
Hills 600-1500 ridge line involved the
33d Division in a battle of larger scale
than had been anticipated. From 19
through 22 February troops of the 130th
and 136th Infantry Regiments, at the
cost of approximately 35 men killed and
75 wounded, fought successfully to clear
the last Japanese from the north-central
section of the ridge line. Some 400 Japanese,
most of them from the 1st Battalion
of the 71st Infantry, 23d Division,
were killed in the area. The few Japanese
who did not hold out to the death

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withdrew southward to join compatriots
on the Hill 600 complex.

As of the beginning of the last week
of February, the Japanese had rebuffed
all 33d Division efforts to secure Hill
600 and to push into the Arodogat Valley
to the east. It appeared that the division
would have to spend so much time and
effort securing the valley and the Hills
600-1500 ridge line that the proposed
concentration on the coast for a move
on San Fernando would be delayed unduly.
The effort that could be expended
on patrolling northward would also be
circumscribed. Moreover, the 33d Division's
patrolling had disclosed to Sixth
Army the very significant fact that the
Japanese withdrawals on the Baguio
front had resulted in considerable
strengthening of the defenses in front
of that city. Manifestly, the 33d Division
was not strong enough to hold a defensive
line, clear the Hills 600-1500 ridge
line, secure the Arodogat Valley, advance
toward San Fernando, patrol northward
throughout its area of responsibility, and
still mount an attack against the strengthened
Japanese defenses around Baguio.

From the first Sixth Army had known
that two divisions would be needed to
achieve decisive results on the Baguio
front, and the operations of the 33d
Division confirmed that opinion. But
even as Sixth Army was obtaining this
confirmation, Krueger had to reassess
the idea that the 32d Division might be
swung northwest against Baguio while
the 33d moved on San Fernando.

The southern boundary of the sector
that the 32d Division began taking over
on 27 January ran from Urdaneta, on
Route 3, across a spur of the Caraballo
Mountains to Route 5 at barrio Digdig,
extending thence along Route 100 to
Carranglan.15
On the northwest, the
32d-43d (and later 33d) Division
boundary ran east from Pozorrubio to
the Arboredo River valley and then
northeast to Malatorre, on the Agno
some eight miles north of San Manuel.
From Malatorre the boundary swung
north to Sapit, near the headwaters of
the Arboredo and about four miles
southeast of Camp 3, the Route 11
strongpoint on the 23d Division's new
MLR.

In the southern part of the 32d Division's
sector the terrain rose slowly to
the east. The most important town in
the sector was Tayug, on the east side
of the Agno and at the junction of roads
from Urdaneta, San Manuel, and San
Quintin. From Tayug, Route 277 runs
northwest five miles to the Cabalisiaan
River at Santa Maria, where the Villa
Verde Trail begins its steep ascent into
the Caraballo Mountains. Another road
runs east-northeast five miles from Tayug
to Batchelor, when a rough trace swings
northeast to Valdes, six miles into the
Caraballo spur. Valdes was a trail center
from which foot patrols could strike
north through the spur toward the Villa
Verde Trail, northeast toward Santa Fe,
and east to Route 5.

For the first five miles or so of its
length north from Santa Maria, the
Villa Verda Trail twists up the east side
of a rough, bare, mile-wide ridge bounded
on the east by the Cabalisiaan River
and on the west by the Ambayabang.
This portion of the trail was negotiable

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for jeeps in 1945, but beyond that there
was a fifteen-mile stretch--counting the
various twists and turns--over which
even foot troops would have trouble
making their way and over which supply
movements would be extremely difficult.
At the northeast end of the trail there
was a five-mile stretch, between Imugan
and Santa Fe, that light trucks could
negotiate.

The 32d Division's first mission was
to move in strength north, northeast,
east, and southeast roughly five miles
beyond Tayug, simultaneously patrolling
up the river valleys and east across
the Caraballo spur. The division reached
its new line by 1 February without opposition
and during the next two days
pushed its center on to Santa Maria, at
the same time starting on its reconnaissance
missions. Division patrols operating
west of the Villa Verde Trail soon
ran into counterreconnaissance screens
in the Arboredo and Agno River valleys.
The Japanese strengthened the Ambayabang
Valley, undefended in early February,
after the middle of the month,
and the 32d Division quickly learned
that the Japanese were preparing to
defend all three valleys.

From the beginning the chief value
of the valleys had been the possibility
that movements along them would
achieve tactical surprise. When it was
learned that chances to gain surprise had
passed, the logistical problems involved
in supporting any attack through the
valleys began to outweigh whatever
tactical advantages might redound from
operations along those routes of approach.
The idea that the 32d Division
might be able to swing northwest toward
Baguio through the valleys began
to look less attractive.

To the east, meanwhile, the 32d Division
had sent a battalion up the Villa
Verde Trail in a reconnaissance-in-force.
By the evening of 7 February, having
been opposed every step of the way from
Santa Maria, the battalion had broken
through a series of minor outpost positions
and, about two and a half miles
north-northeast of Santa Maria, had
reached the principal Japanese OPLR
defenses on the Villa Verde Trail. Since
a major effort would be required to dislodge
these Japanese, the 32d Division
held what it had, having been instructed
to avoid a large-scale battle. As it was,
by discovering that about a battalion of
Japanese defended the southern section
of the Villa Verde Trail, the division
had successfully accomplished its initial
reconnaissance mission in that sector.

Small groups from the 32d Division
had been patrolling across the Caraballo
spur while the division was moving
units up the Villa Verde Trail and the
river valleys, and the reports brought
back by patrols operating in the mountains
were of considerable importance to
future Sixth Army plans. First, the
patrols discovered that most of the trails
through the spur seemed to have been
used before February 1945 by wild pigs
rather than human beings. The ground
proved to be so rough that the logistical
support of any large force attempting
to use the trails as a means of outflanking
Japanese defenses on either Route
5 or the Villa Verde Trail would be
virtually impossible.

Next, the few patrols that had managed
to reach the northeast section of
the Villa Verde Trail in the vicinity of
Imugan reported that the Japanese
were sending reinforcements west along
the trail. This route of approach to

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VILLA VERDE TRAIL NEAR SAN NICOLAS

Bambang, it appeared, was going to be
more strongly defended than anticipated.
If so, the 32d Division was going to be
hard put to divert any effort at all toward
Baguio. Furthermore, 32d Division
patrols penetrating as far as Route
5 learned that the stretch of highway
north of Digdig was obviously going to
be the scene of a major Japanese defensive
effort. As events turned out, the
results of this patrolling would prove of
more importance to the 25th Division
than to the 32d, but the possibility that
the 25th rather than the 32d might become
responsible for securing Route 5
north of Digdig was not, apparently,
even a dream when, in early February,
the 25th Division started patrolling north
from San Jose.

Like the 32d, the 25th Division had
both reconnaissance and holding missions
until late February.16
The line
that the division was required to hold
lay east and west of Rosaldo, a tiny

--462--

barrio on Route 5 about five miles northeast
of San Jose. West of Route 5 the
"secure line" lay about a mile into the
Caraballo spur and paralleled Route 8,
running northwest from San Jose to
Umingan. East of Rosaldo the line extended
three miles to Mt. Bolokbok,
whence it swung generally south along
the Pampanga River to Rizal, at the
southern end of Route 100 and ten miles
southeast of San Jose. The division
would reconnoiter north of this line to
the 25th-32d Division boundary, crossing
Route 5 at Digdig.

Patrols of the 25th Division operating
in the southern section of the Caraballo
spur found the terrain even worse than
that in the Valdes region to the north.
More important, division units that
managed to traverse the spur discovered
that the Puncan area was strongly defended,
providing Sixth Army with the
first indication of the 10th Division's intention
of stationing a delaying force of
one RCT across Route 5 at that point.

In the center, along Route 5, the 25th
Division sent a battalion-sized reconnaissance-in-force up the highway just as the
32d Division had pushed a battalion up
the Villa Verde Trail. The results were
nearly identical. The 25th Division's
battalion reached Rosaldo on 14 February
and a week later, having probed cautiously
northward, was in contact with
an organized Japanese delaying position
another five miles up the highway. Any
further effort would obviously involve
major operations. Therefore, its reconnaissance
mission accomplished, the 25th
Division halted its battalion just as the
32d Division had stopped its unit on the
Villa Verde Trail.

To the east other 25th Division patrols,
their reports augmented by information
acquired from guerrillas, found
substantial indications that the Japanese
were going to defend both Route 100
and the Old Spanish Trail. By 21 February
it was clear that the Japanese were
not missing any more defensive bets on
the 25th Division front than they were
in the zones of the 32d and 33d Divisions.

Thus, I Corps operations on the
Baguio and Bambang fronts during the
first three weeks of February made it
obvious that the Japanese were going to
defend every avenue of approach to the
north, with the possible exception of
Route 3 on the west coast. There, 33d
Division reconnaissance had not carried
sufficiently far northward to draw any
conclusions about Japanese defenses.
The Japanese withdrawal in front of
Baguio, Sixth Army had learned, did
not indicate weakness but actually foreshadowed
a tightening and strengthening
of defensive lines. Sixth Army had
expected to find strong defenses on
Route 5, but it now appeared that the
Japanese were willing and able to devote
greater effort to the defense of the river
valleys, the Villa Verde Trail, Route
100, and the Old Spanish Trail than
Sixth Army's G-2 Section had at first
estimated.

From the beginning of planning, General
Krueger had realized that I Corps
would need at least two divisions to
achieve decisive results on the Baguio
front. Now it was also obvious that the
corps would require two divisions on
the Bambang front in order to mount
even a limited-objective holding attack.
But I Corps had only three divisions
available. It was time to reassess plans
with a view toward deciding along which
front the more decisive results could be
achieved.

--463--

BAGABAG

Guerrillas and Additional
Intelligence

While I Corps was busy gathering
important information through ground
reconnaissance, other intelligence poured
into Sixth Army headquarters from aerial
reconnaissance, guerrilla reports, captured
documents, and, presumably,
radio intercepts. Through a combination
of these sources Sixth Army, during
the first weeks of February, learned of
the Shobu Group's plan for the triangular
defensive redoubt. Of perhaps greater
importance for future planning was the
discovery of the Baguio-Aritao supply
road. Sixth Army had previously considered
the Baguio and Bambang defensive
sectors to be more or less isolated
from one another, but the existence of
the supply road made it apparent that
the Japanese could rapidly move troops
from one front to the other. If that link
in the Japanese defensive system could
be severed, Sixth Army would achieve a
significant tactical success. A decision
had to be made selecting the front on
which to put the effort necessary to close
one end of the supply road.

The distance from the 33d Division's
front lines on Route 11 to the Baguio
end of the supply road was shorter than

--464--

that from the 25th Division's advanced
position on Route 5 to Aritao. But on
the Baguio side the approach ran all the
way through easily defensible terrain,
whereas north of Santa Fe the terrain to
Aritao was fairly open. Other factors
favored the Route 5 approach. Having
learned of Yamashita's triangular defense
concept, Krueger foresaw that a
I Corps advance up Route 5 would not
only threaten the Aritao terminus of the
supply road but would also pose a direct
threat to the Bambang anchor of the triangle.
Moreover, not too far beyond
Bambang lay the junction of Routes 4
and 5 at Bagabag. If I Corps seized that
junction, it would cut the triangular
redoubt off from supplies in the Cagayan
Valley except for what the Japanese
could move over Route 11 from Tuguegarao,
a stretch of miserable road that
guerrillas constantly blocked. The capture
of both the Routes 4-5 junction and
the Aritao entrance to the supply road
would not only open two additional
routes over which Sixth Army troops
could advance into the Shobu Group
redoubt but would also open the way
into the Cagayan Valley, an eventuality
that promised to cut off strong Japanese
forces from the rest of the Shobu Group.
All in all, it appeared that if the Sixth
Army could push to and beyond Aritao
the Shobu Group would face disaster.
Such decisive results could not be
achieved on the Baguio front, for from
Baguio the Shobu Group forces could
make a fighting withdrawal along easily
defensible Route 11, retiring even further
into the mountains while continuing
to receive supplies from the Cagayan
Valley. Finally, by the third week in
February, Krueger had decided it would
be unsound to reorient the 32d Division
from the firm contact the unit had established
along the Villa Verde Trail,
such an obvious route to outflank the
Shobu Group's Route 5 defenses.
Krueger's decision would have to favor
the Bambang front.

Before the end of February, then,
Krueger had had to reorient Sixth
Army's plans completely. The 25th and
32d Divisions would make the major
effort against the Shobu Group, striking
north on the Bambang front. The
Baguio front Krueger relegated to a
holding status. There, until the 37th
Division could move north from Manila,
the 33d Division would have a
supporting, secondary role.

While making these decisions, Krueger
still had to worry about the Japanese
19th Division, which, he knew by mid-February, had withdrawn from the
Baguio region. He learned that the division
was moving north toward the
hitherto undefended Bontoc area, northern
apex of Yamashita's triangular redoubt.
For obvious reasons, Krueger
wanted to contain the 19th Division in
the Bontoc area, but with all available
American divisions committed to definite
courses of action on the Baguio or
Bambang fronts, he could spare no
troops for the job of pinning the 19th
Division in place. There was, however,
a force upon which he could depend for
help--the United States Army Forces in
the Philippines, Northern Luzon.

Usually known as the USAFIP(NL),
this organized guerrilla force was led by
Col. Russell W. Volckmann, a U.S. Army
regular who, at the risk of sudden death
at the hands of the Japanese (if not ultimate
court-martial by the U.S. Army for
disobeying surrender orders) had taken
to the hills upon the fall of the Philippines

--465--

in 1942.17
When Sixth Army
reached Luzon on 9 January Colonel
Volckmann's force had numbered about
8,000 men, of whom only 2,000 were well
armed. After the invasion Sixth Army
started running supplies to the
USAFIP(NL), first by small craft that
put into various guerrilla-held beaches
on the west coast and later by C-47 aircraft
that flew to guerrilla-held dropping
grounds and airstrips. Within two
months after the landing at Lingayen
Gulf, Filipino enthusiasm had brought
Volckmann's strength up to 18,000 men,
while the supply of arms increased not
only because of Sixth Army's efforts but
also because their own new strength enabled
the guerrillas to capture equipment
from isolated Japanese outposts
and patrols.

Volckmann divided his organization
into command, combat, and service echelons,
respectively numbering 1,400,
15,000, and 2,700 troops. The combat
echelon was in turn broken down into
five infantry regiments--the 11th, 14th,
15th, 66th, and 121st--each with an
"authorized" strength of 2,900 officers
and men, and each subdivided into three
rifle battalions of four rifle companies
apiece. The combat echelon was soon
strengthened by the addition of a battalion
of mixed field artillery, equipped
with captured Japanese ordnance.

At the beginning of February Volckmann's
headquarters was at Darigayos
Cove, on the coast about fifteen miles
north of San Fernando. His missions as
assigned by Sixth Army, which assumed
control of USAFIP(NL) on 13 January,
were to gather intelligence, ambush Japanese
patrols, seize or destroy Japanese
supplies, disrupt Japanese lines of communication,
and block Japanese routes
of withdrawal into and exit from the
Cagayan Valley.18
It was not, apparently,
initially intended that Volckmann's
force would engage in sustained efforts
against major Japanese units, and there
seems to have been little hope that
Volckmann's, or any other guerrilla
unit, would ever become effective combat
organizations. The most help GHQ
SWPA and Sixth Army probably expected
was in the form of harassing
raids, sabotage, and intelligence.

But Volckmann--and other guerrilla
leaders on Luzon as well--interpreted
his missions as broadly as his strength
and armament permitted. By the end
of February USAFIP(NL) had cleared much of the west coast of Luzon north
of San Fernando and also controlled the
north coast west of Aparri. Volckmann
had rendered Route 11 between Baguio
and Tuguegarao and Route 4 from Libtong
to Bagabag virtually impassable to
the Japanese. Indeed, as has been shown,
one of the main reasons that Yamashita
moved the 19th Division north had
been to regain control over the two
vital highways so that supplies could
continue moving into the final redoubt.
While USAFIP(NL) did not possess sufficient
strength to attack major Japanese
concentrations or to hold out against
large-scale punitive expeditions, it had
diverted and pinned down Japanese
forces that could undoubtedly have been
used to better advantage elsewhere. It
would appear that by mid-February

--466--

USAFIP(NL) had accomplished far more
than GHQ SWPA or Sixth Army had
either expected or hoped.

While Sixth Army had probably not
planned to use guerrillas extensively, it
seems that the loss of the 40th and 41st
Divisions, coupled with the other difficulties
involved in securing sufficient
regular troops for operations in northern
Luzon, prompted General Krueger
to reassess the role guerrillas could and
would play.19
During February more
and more guerrilla units were outfitted
with weapons and clothes, some of them
relieving regular forces in guard duties
and mopping-up actions while others
were sent to the front for direct attachment
to and reinforcement of combat
units. In the case of USAFIP(NL), supply
efforts were redoubled, a broad program
of air support was set up and air
support parties were sent to Volckmann,
and, as time passed, Volckmann's missions
were enlarged. Indeed, Volckmann's
forces came to substitute for a
full division, taking the place of the
regular division that Krueger had
planned to send up the west coast in a
series of shore-to-shore operations, an
undertaking that, by mid-February,
USAFIP(NL) successes had rendered
unnecessary.

The Plan in Late February

Thus, as of late February General
Krueger had available for operations in
northern Luzon the 25th, 32d, and 33d
Divisions and the USAFIP(NL) as a
substitute for a fourth division. He expected
the 37th Division to become
available, one RCT at a time, beginning
in late March.

With these forces, Sixth Army's plan
called for the first main effort in northern
Luzon to be made on the Bambang
front by the 25th and 32d Divisions.
Meanwhile, the 33d Division would
mount holding attacks on the Baguio
front, which would explode into decisive
action once the 37th Division, released
from its garrison duties at Manila,
moved north. Initially, USAFIP(NL)
would continue its harassing missions
and provide such help in the San Fernando
and Baguio areas as was feasible.
(Two of its battalions had been fighting
under 43d and then 33d Division control
since late January and other units were
already moving toward San Fernando.)
When the 37th Division began moving
into position on the Baguio front,
USAFIP(NL) would undertake a drive
inland along Route 4 toward the junction
of Routes 4 and 11 at Bontoc.

These plans had not emerged all of a
piece from the G-3 Section of Sixth
Army headquarters. The concept of
making the main effort along the Bambang
approaches developed during the
first three weeks of February; the final
plans for the employment of the 37th
Division and USAFIP(NL) did not develop
much before mid-March; the idea
that the 33d Division would have a
holding mission until the 37th Division
reached the Baguio front was clear well
before the end of February.

Footnotes

1. For details of the redeployment and reduction
directives of early February, see Chapter XX, above.

2. For the background of Yamashita's triangular
defense concept, see above, Chapter V. Information
on the initiation of the Shobu Group's withdrawal is
set forth in Chapter IX and XI.

3. Actually, there is no broad valley connection
between the Magat and Cagayan River valleys, for
the Magat, the Cagayan's major tributary, runs
through a canyon before it joins the Cagayan. On
the other hand, Filipino usage usually applies the
name Cagayan Valley to that portion of the Magat
Valley south of the canyon.

17. Additional information on the USAFIP(NL) is
derived from USAFIP(NL) Operations Report, pages
3-6, 8, 10-17. Volckmann held the rank of major
in 1942. He was promoted to lieutenant colonel in
October 1944 and to colonel in February 1945.

19. The fact that Krueger established machinery for
controlling guerrillas in a Special Intelligence Section
under his G-2 seems indicative of the limited
use to which Sixth Army, at least initially, intended
to put guerrillas.